A substantial portion of electronics equipment used in the telecommunications and other industries is manufactured and put in service in modular form. Various modular subassemblies are then combined to make up a unit or item of electronics equipment. These modules are generally housed together in a single chassis, such as a rack or cabinet. For example, a power system that has several rectifier components may provide for a separate module to hold each rectifier, all of which is housed together in a single rack or cabinet.
Most modules have a conductive metal case with a multi-pin electrical connector on the rear wall. The cabinets and racks are generally configured to support the modules on shelving attached to a chassis. The shelving may also have sidewalls to compartmentalize the modules and guide mechanisms to position the module so the electrical connector on the module engages a corresponding electrical connector on the chassis. In most cases the chassis of the rack or cabinet also supports and carries the wiring from an external power source to the modules as well as providing a path for the wiring to provide electrical interconnectivity between modules. While a number of prior art cabinet and rack designs exist to hold electronics modules, they all share one common feature, which is the shelving that is used to hold and support the electronics modules.
The current trend in the electronics industry is towards smaller, more compact and dense electronics systems and equipment with more complex circuits. Increased circuit complexity usually means more space is required for components, which conflicts with the trend towards smaller, more compact electronics systems. This dilemma has been solved, in part, by the structural design and arrangement of the cabinets and racks housing the modules.
A typical cabinet or rack that is used to house such modules consumes a surprisingly significant volume of space. Because shelving is designed to structurally support a number of electronics modules, the shelving is reinforced by crossbars or some other method to add to shelf stiffness in order to support the weight of the modules. Other methods to add stiffness include folding the shelf edge into a supporting structure and molding indentations into the shelves to add stiffness. In each case where a shelf supports weight, stiffness is directly related to thickness. This thickness then consumes cabinet volume that could be used to house active electronics. For example, if a shelf holds 3.5 inch high modules has a total thickness of three-eighths of an inch, approximately 9.67% of the cabinet volume available for shelving and modules is occupied by shelving. Thus, a significant problem with these conventional chassis is that a significant amount of volume is occupied by the support and shelving structures.
Therefore, what is needed in the art is a device to secure and support electronics modules in a cabinet or rack without sacrificing any more internal housing volume than is necessary.